implemented current schoolyear API and dynamic timetable scroll boundaries, added handling for out-of-range errors to narrow accessible dates, optimized holiday region rendering by collapsing overlaps, and refined holiday tile UI

lib/view/pages/timetable/widgets/special_regions_builder.dart

@@ -62,33 +62,47 @@ class SpecialRegionsBuilder {
 
   static String _dayKey(DateTime d) => '${d.year}-${d.month}-${d.day}';
 
-  Iterable<TimeRegion> _buildHolidayRegions() => holidays.result.expand((
-    holiday,
-  ) {
-    final startDay = WebuntisTime.parse(holiday.startDate, 0);
-    final endDay = WebuntisTime.parse(holiday.endDate, 0);
-    // Webuntis treats endDate inclusively (last day of the break) — the
-    // `+ 1` covers single-day public holidays (where startDate == endDate)
-    // and the final day of a multi-day vacation, both of which would
-    // otherwise be skipped.
-    final dayCount = endDay.difference(startDay).inDays + 1;
-    final days = List<DateTime>.generate(
-      dayCount,
-      (i) => startDay.add(Duration(days: i)),
-    );
+  Iterable<TimeRegion> _buildHolidayRegions() {
+    // Multiple Webuntis holiday entries can cover the same day (e.g. a
+    // public holiday falling inside a vacation period). Collapse them
+    // per-day so we emit exactly one TimeRegion per day and the
+    // overlapping labels don't render on top of each other.
+    final byDay = <String, _HolidayDay>{};
+    for (final holiday in holidays.result) {
+      final startDay = WebuntisTime.parse(holiday.startDate, 0);
+      final endDay = WebuntisTime.parse(holiday.endDate, 0);
+      // Webuntis treats endDate inclusively (last day of the break) — the
+      // `+ 1` covers single-day public holidays (where startDate == endDate)
+      // and the final day of a multi-day vacation, both of which would
+      // otherwise be skipped.
+      final dayCount = endDay.difference(startDay).inDays + 1;
+      for (var i = 0; i < dayCount; i++) {
+        final day = startDay.add(Duration(days: i));
+        final key = _dayKey(day);
+        byDay.putIfAbsent(key, () => _HolidayDay(day, [])).names.add(
+          holiday.name,
+        );
+      }
+    }
     final gridStartHour = kCalendarStartHour.floor();
     final gridStartMinute = ((kCalendarStartHour - gridStartHour) * 60).round();
     final gridEndHour = kCalendarEndHour.floor();
     final gridEndMinute = ((kCalendarEndHour - gridEndHour) * 60).round();
-    return days.map(
-      (day) => TimeRegion(
-        startTime: day.copyWith(hour: gridStartHour, minute: gridStartMinute),
-        endTime: day.copyWith(hour: gridEndHour, minute: gridEndMinute),
-        text: '$kTimeRegionHolidayPrefix${holiday.name}',
+    return byDay.values.map(
+      (entry) => TimeRegion(
+        startTime: entry.day.copyWith(
+          hour: gridStartHour,
+          minute: gridStartMinute,
+        ),
+        endTime: entry.day.copyWith(
+          hour: gridEndHour,
+          minute: gridEndMinute,
+        ),
+        text: '$kTimeRegionHolidayPrefix${entry.names.join(" / ")}',
         color: disabledColor.withAlpha(50),
       ),
     );
-  });
+  }
 
   TimeRegion _breakRegion(DateTime start, Duration duration) => TimeRegion(
     startTime: start,
@@ -98,3 +112,9 @@ class SpecialRegionsBuilder {
     iconData: Icons.restaurant,
   );
 }
+
+class _HolidayDay {
+  final DateTime day;
+  final List<String> names;
+  _HolidayDay(this.day, this.names);
+}